Combination Vaccination and Broadly Neutralising Antibody Therapy in HIV

There is no cure for HIV infection. Antiretroviral therapy (ART) is widely available but requires daily, life-long intake. This can cause issues around side-effects, resistance, adherence and stigma. A new therapy, broadly neutralising antibodies, (bNAbs), may work as well as ART and may last longer - one dose can last six months. bNAbs appear to first target HIV viruses, then drive a protective immune response conferring long-term control, called the vaccinal effect. AbVax is a clinical trial to understand this effect and how to enhance it to give the strongest possible long-term protection for people living with HIV (PWH). The investigators are studying whether a combination of vaccines that attack HIV, a short period of treatment interruption induced viraemia (TIIV - stopping ART for a few weeks to allow a small amount of virus to return to the bloodstream) and bNABs will produce the most sustained immune protection.

AbVax will recruit 48 otherwise healthy PWH aged 18-64. Participants will be randomised across three groups (arms) to determine the best combination of treatment. In Arm A, participants will undergo a period of TIIV, then receive two bNAb infusions. In Arm B, participants receive a combination of three HIV vaccines (one prime dose followed by two booster doses after 4 and 16 weeks), then are given two bNAb infusions. In Arm C, participants will undergo a period of TIIV, then receive the same vaccination combinations as Arm B, then receive two bNAb infusions. All participants then stop ART for an analytical treatment interruption (ATI) to determine the clinical impact and measure how long before any HIV returns to the blood. This allows the investigators to see if vaccines and TIIV add to the protection provided by bNAbs and by how much.